Neat stuff. I actually used to be quite intrigued by cryonics, but then I stopped thinking about it. Death used to be more terrifying to me. I don’t like the prospect now, but I have developed an uneasy peace with the concept.

I want to live for a long time, of course, and getting terminal news tomorrow would be devastating. But I’ve reached a point where I can honestly say I feel I’ve lived a good life already. I want more, but existence hasn’t given me the short end of the stick.

Still…it would be nice to just keep going and going. Two hundred years. Five hundred years. Three thousand years. Thing is, I’m not as convinced as you probably are that life extension and immortality is just the foolish stuff of sci-fi fantasy.

Some seriously smart people think this is coming.

Ray Kurzweil is an MIT grad and the director of engineering at Google. He’s also a well-known voice in this conversation. His book The Singularity is Near argues for an imminent machine personhood as well as future “immortality” through digital upload of human consciousness. It’s persuasive reading and he makes a compelling case. Future forecasters are frequently wrong, of course, and the point isn’t that he’s right – only that he shouldn’t be off-handedly dismissed.

A digital future is one of the ways some experts in the field see immortality developing, and it could. What I take issue with, though, is a philosophical conundrum at least as old as the ancient Greeks: what makes something what it is.

Is a digital copy of Eric still Eric? I don’t think it is. It’s still better than me disappearing entirely, I suppose, but (at best) it’s a new digital being with my memories, not actually “me”.

Maybe. It gets more complicated. What if the transfer doesn’t happen in a single upload event? What if, instead, there is a cyborg intermediary phase, in which the digital world becomes part of our physical bodies, and we slip seamlessly back and forth within our brains from using our organic hardware and our computer hardware? And what if over a lifetime we gradually start using the digital world more than the real world? What is the point where we stop being us and start being a new being? Or does this gradual transition mean there’s a personality continuum, therefore a continuum of identity, i.e. we’re still the same person?

Think about it: our cells are replaced on an ongoing basis, but we’re still “us” aren’t we?

It’s mind-bending stuff.

So, cryonics and digital uploads. Neither is ideal, in my book. Cryonics means dying with no idea if you’re coming back and digital uploading seems more like a record of your life than continued life.

No, the immortality I want would be achieved through some sort of gene therapy, likely buttressed with cell reconstruction and medicine compliments of nanotechnology.

My understanding of the role cells play in aging is that, in addition to accumulated radiation leading to greater and greater mutations, cell division has a lifespan: each time a cell divides, the number of times its “offspring” can divide decreases – an actual, physical thing called a telomere shortens with each division, and when a new cell doesn’t have enough telomere left, it can’t divide.

Death may be physically hardwired in our cells. Cells are subject to the laws of physics, and we’re getting better at using those laws (check out this movie made with atoms: http://www.youtube.com/watch?v=oSCX78-8-q0)

Again, physical problems – an “engineering problem” – with emerging technology that may provide a remedy.

The point is not that you will stop reading this post and definitely believe humans will live forever. The point is that dismissing extreme longevity/immortality as a patently absurd concept means you’re uninformed.

We might not get there, of course – especially if we suffer some sort of catastrophic setback in humanity’s cultural and scientific advance – but it’s time we start having a conversation about what it would mean if people just didn’t die.

My guess is we can barely begin to conceive of how radically that would change who we are, what we value, and how our species will develop in coming centuries.